Plate heat exchangers of a type generally corresponding to those corresponding to the present invention are shown in EP 14 00 772 A2 (assigned to the assignee of this application, published Mar. 24, 2004) and corresponding U.S. Publication No. 2004/112579 A1 (also assigned to the assignee of this application, and published Jun. 17, 2004), the full disclosures of which are hereby incorporated by reference. The plate heat exchanger disclosed therein is suitable for heat exchange between media under a relatively high pressure, as prevails, for example, in an air conditioning loop on the refrigerant side. However, while those publications disclose an advantageous pressure-stable design of the collecting and distribution channels (i.e., the output and input) for the refrigerant (e.g., CO2) passing through the stacked plates, they disclose flow channels between the plates for CO2 gas which the present invention may advantageously improve upon.
WO 03/054468 A1 discloses a device for exchanging heat which is also a component of an air conditioning loop. In this device, all of the heat exchanger plates are difficult to manufacture, and the device may be viewed as still taking up more space than desired in many applications in which space limitations are critical. In these respects, the heat exchanger disclosed in WO 01/69157 A2 (corresponding to U.S. Publication No. 2004/26071 A1) appears to be more advantageous for a vehicle air conditioner. However, a so-called intermediate heat exchanger is otherwise disclosed in which refrigerant at a higher temperature is in heat exchange with the same refrigerant at lower temperature. Fine channels are provided there in all the flow channels of the heat exchanger, which channels are produced by manufacturing methods involving addition or removal of material on or in the heat exchanger plates.
The present invention is directed toward overcoming one or more of the problems set forth above.